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Message-Id: <1346937043-28208-5-git-send-email-gerald.schaefer@de.ibm.com>
Date: Thu, 6 Sep 2012 15:10:39 +0200
From: Gerald Schaefer <gerald.schaefer@...ibm.com>
To: Andrew Morton <akpm@...ux-foundation.org>,
Andrea Arcangeli <aarcange@...hat.com>,
Andi Kleen <ak@...ux.intel.com>,
Hugh Dickins <hughd@...gle.com>,
Hillf Danton <dhillf@...il.com>
Cc: linux-kernel@...r.kernel.org,
Martin Schwidefsky <schwidefsky@...ibm.com>,
Heiko Carstens <heiko.carstens@...ibm.com>,
Ingo Molnar <mingo@...nel.org>,
Thomas Gleixner <tglx@...utronix.de>,
"H. Peter Anvin" <hpa@...or.com>,
Gerald Schaefer <gerald.schaefer@...ibm.com>
Subject: [PATCH 4/8] thp: make MADV_HUGEPAGE check for mm->def_flags
This adds a check to hugepage_madvise(), to refuse MADV_HUGEPAGE
if VM_NOHUGEPAGE is set in mm->def_flags. On s390, the VM_NOHUGEPAGE
flag will be set in mm->def_flags for kvm processes, to prevent any
future thp mappings. In order to also prevent MADV_HUGEPAGE on such an
mm, hugepage_madvise() should check mm->def_flags.
Signed-off-by: Gerald Schaefer <gerald.schaefer@...ibm.com>
---
mm/huge_memory.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 5617ee0..5fa0cd3 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1464,6 +1464,8 @@ out:
int hugepage_madvise(struct vm_area_struct *vma,
unsigned long *vm_flags, int advice)
{
+ struct mm_struct *mm = vma->vm_mm;
+
switch (advice) {
case MADV_HUGEPAGE:
/*
@@ -1471,6 +1473,8 @@ int hugepage_madvise(struct vm_area_struct *vma,
*/
if (*vm_flags & (VM_HUGEPAGE | VM_NO_THP))
return -EINVAL;
+ if (mm->def_flags & VM_NOHUGEPAGE)
+ return -EINVAL;
*vm_flags &= ~VM_NOHUGEPAGE;
*vm_flags |= VM_HUGEPAGE;
/*
--
1.7.11.5
--
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